SITU-PAN

by: Chris Pressey

Publication date: 2015-07

Topics: Retrocomputing, Front panel simulators, DIP switches

Item Size: 57.2K

SITU-PAN is a front-panel simulator for the Commodore 64. It can be used to enter bytes into memory, and it was used for this purpose in the Bootstrap Zero project during RetroChallenge 2015/07.

The screen shows an approximation of 8 LEDs and 8 SPST switches that would be connected to the 8 data lines on a real front panel.

The keys on the bottom row of the keyboard move each switch down; the keys in the 2nd-to-bottom row move each switch up. (In an effort to be more realistic, they are not toggled by a single key.)

Pressing Return causes the binary value selected by the switches to be written to the current address in RAM. That value is then reflected in the LEDs.

Other simulated buttons (not shown in the UI) are

=, which advances the address by one (you typically press this every time you are happy with the current byte you have written,)
& which resets the address to the beginning of memory (which can be used to review the bits you’ve entered by stepping through them with = and watching the LEDs), and
! to execute the machine code at the current address.